Driven by application services that are based on multimedia network technologies, with requirements of people on bandwidth, a transmission capacity of a communications network increases dramatically. Because a conventional electrical network cannot provide a low-cost solution for a high-capacity communications network, a bottleneck of network bandwidth is shifted from an optical layer of a network to a network layer. Therefore, a dynamic, transparent, and reconfigurable optical network attracts more attention of people and develops rapidly.
The optical network is developed not only in terms of continuous improvement of a transmission rate, intelligence of the optical network is also continuously improved. Intelligent management requires that a state and a signal of a network need to be monitored in real time, thereby performing dynamic control. Therefore, it is quite necessary to determine a parameter and a state of health of a network physical layer in an optical domain. Optical performance monitor (OPM), as a function module for monitoring indicators such as optical power of a channel, a center wavelength, and an optical signal-to-noise ratio (OSNR) online (in the optical domain), has attracted attention of people. The optical performance monitor can provide reliable, accurate, and real-time information for the optical network, and has become an important link of optical network management.
Currently, an OPM module monitors an optical performance parameter mainly based on an optical spectrum analysis technology, that is, the OPM module generally uses a tunable filter and a homodyne detection technology to extract an optical spectrum characteristic to monitor multiple parameters. The tunable filter needs to filter out each single-wavelength optical signal, and monitors each single-wavelength optical signal, so as to estimate the optical performance parameter.
However, because the filter used by the OPM module causes severe damage to a signal, precision of detecting the optical performance parameter by the OPM module is relatively low.